1. Field of the Invention
This invention relates to an apparatus for unwinding a web roll, and particularly to an apparatus for unwinding a roll of a thin belt-like discrete sheet material (hereinafter referred to as a "web") including paper, plastic film, fabric, metal and the like.
2. Description of the Prior Art
In a known apparatus for unwinding a web roll, the web roll is supplied from the storing section to an unwinding section, a core of the web roll is secured to an unwinding shaft, and a tensile force in the unwinding direction is applied to the forward end portion of the web to unwind the web. When the web roll was not supplied from the storing section to the unwinding section under conditions where the tensile force was applied to the forward end of the web, forming failures would be caused. The above-described problem has heretofore made it difficult to automate the mounting operation of the web roll.
There has been proposed a device for automatically supplying a web roll as disclosed in Japanese Kokai No. 51371/78, in which, however, an arrangement has been adopted such that the unwinding shaft position is fixed and the web roll supply position is movable, thus presenting disadvantages in that the mechanism is complicated and the space required for installation is increased.